E6B Calculator
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Wind Correction Angle Calculator

True course, airspeed and wind in; wind correction angle, heading and ground speed out, with the wind triangle drawn.

Heading and ground speed

Wind correction angle, true heading and ground speed for a true course.

°
kt
°
kt

Optional. From the chart's isogonic line.

True heading076°
Ground speed88 kt
Wind correction angle14° left
Headwind component28 kt
Crosswind component28 kt from the left
NTH 076°W 40GS 88
How it is calculated
  1. Wind angle = wind 045° − course 090° = −45° (wind from the left).
  2. Crosswind = 40 × sin 45° = 28.3 kt; headwind = 40 × cos 45° = 28.3 kt.
  3. Wind correction angle = arcsin(28.3 ÷ 120) = 13.6°, turned into the wind (left).
  4. True heading = 090° − 13.6° = 076°.
  5. Ground speed = 120 × cos 13.6° − 28.3 = 88.3 kt.

Find the wind

The wind aloft from the heading you held and the track and ground speed you made good.

°
kt
°
kt
Wind044° at 41 kt
Drift angle14° right
How it is calculated
  1. Air vector: 120 kt toward 076°. Ground vector: 88 kt toward 090°.
  2. Wind vector = ground vector − air vector: 40.6 kt, blowing from 044°.
  3. Drift = track − heading = +14.0°.

The wind triangle

Three vectors make up every wind problem:

To fly a planned true course you point the nose into the wind by the wind correction angle (WCA), so that the sum of the air and wind vectors lies along the course. The diagram in the result draws the triangle to scale: heading in white, wind in cyan and the resulting ground track in green along the magenta course line.

The worked example

This is the chapter 16 example from the Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C). A true course of 090° at 120 knots with the wind from 045° at 40 knots:

  1. The wind comes from 45° left of the course.
  2. Its crosswind component is 40 × sin 45° = 28.3 knots and its headwind component is 40 × cos 45° = 28.3 knots.
  3. WCA = arcsin(28.3 ÷ 120) = 13.6°, to the left.
  4. True heading = 090° − 13.6° = 076°.
  5. Ground speed = 120 × cos 13.6° − 28.3 = 88 knots.

The handbook's plotted answer is the same: heading 076°, ground speed 88 knots, 14° left correction. At that ground speed its 220 nautical mile trip takes 2 hours 30 minutes.

From true heading to compass heading

The heading chain in flight planning is TC ± WCA = TH ± V = MH ± D = CH. Enter the chart's magnetic variation (for example 7E or 12W) and the result adds the magnetic heading: east variation is subtracted and west variation added ("east is least, west is best"). Compass deviation comes from the card mounted by the compass; the VFR nav log carries it for each leg.

Finding the wind in flight

The second calculator works backwards. Hold a heading, note the airspeed, and time a leg between two checkpoints to get your track and ground speed. With the example's rounded numbers (heading 076°, 120 knots, track 090°, ground speed 88 knots), it finds a wind of about 044° at 41 knots. That is within a degree and a knot of the forecast 045° at 40; rounding the heading to whole degrees explains the difference.

When there is no answer

If the crosswind component is as large as your true airspeed, no heading holds the course. If the headwind exceeds your airspeed, you cannot make progress. The calculator says so instead of producing a heading.

Wind correction angle on the E6B wind side

  1. Turn the rose until the wind direction is under the TRUE INDEX, set the grommet on a convenient speed arc and mark a dot straight up from it by the wind speed.
  2. Turn the rose until the true course is under the TRUE INDEX.
  3. Slide the grid until the wind dot lies on the true-airspeed arc.
  4. Read the ground speed under the grommet and the wind correction angle on the drift line through the dot; add it to the course if the dot is right of center, subtract it if left.

Questions pilots ask

How do you calculate the wind correction angle?

Find the crosswind component relative to your course, divide it by the true airspeed and take the arcsine. With 28.3 knots of crosswind at 120 knots, the wind correction angle is arcsin(28.3 ÷ 120) = 13.6 degrees, turned toward the wind.

Do I add or subtract the wind correction angle?

Turn into the wind. A wind from the right needs a heading to the right of the course, so add the angle; a wind from the left needs a heading to the left, so subtract it. The calculator shows the direction and the heading.

Is the heading true or magnetic?

With a true course and a true wind (as in winds-aloft forecasts), the result is a true heading. Enter the magnetic variation to get the magnetic heading: subtract easterly variation and add westerly variation.

How does the find-the-wind calculator work?

In flight, if you know the heading you held and the track and ground speed you made good (from checkpoints or GPS), the wind is the difference between the ground vector and the air vector. The calculator solves that triangle backwards.